1. Field of the Invention
The invention relates to a friction drive device including a drive roller and a driven roller which are contacted with each other and transmit torque from one of the drive and driven rollers to the other thereof by using friction force which is caused at their contact portions.
2. Description of Related Art
Related rotary drive devices may be equipped with a damper for preventing vibration that is caused by torque fluctuation. An automobile manual transmission is one example of a related rotary drive device that is equipped with a damper that serves as a torque fluctuation absorbing device. The damper includes a plurality of coil springs, friction elements, and the like. In the related damper, the coil springs are arranged so as to act in a circumferential direction of the damper, that is, in a direction of torque application, because the torque is applied in a rotational direction of the transmission shaft.